A transesterification process for preparing alkoxysilane includes removal of metal transesterification catalyst from the alkoxysilane transesterification reaction medium.

1. The present invention relates to a method for the purification of halogenated oligosilanes as a pure compound or mixture of compounds each having at least one direct Si—Si bond, the substituents thereof being exclusively halogen or halogen and hydrogen, and the composition thereof being an atom ratio of substituent:silicon of at least 3:2, by the action of at least one purification agent on the halogenated oligosilane and isolation of the halogenated oligosilane with improved purity.

2.1. In the prior art, halogenated monosilanes such as HSiCl.sub.3 are purified by treatment with preferably polymeric organic compounds containing amino groups, and are separated out from these mixtures. This method cannot be used for halogenated oligosilanes because of the contained amino groups, since secondary reactions would lead to decomposition of the products. The new method should provide the desired products in high yield and purity without amino groups being used.

2.2. The purification of the halogenated oligosilanes is carried out in the presence of special purification agents, which convert contaminations such as, for example, FeCl.sub.2 into an insoluble and/or less volatile form. A separation of the products of completes the purification This method gives a high yield and avoids the problems associated with the prior art, such as, for example, long distillation times.

2.3. The method is suitable for the purification of, for example, Si.sub.2Cl.sub.6, Si.sub.3Cl.sub.8, Si.sub.4Cl.sub.10, and higher homologs. These find application, for example, in the deposition of silicon nitride layers in CVD processes.

Fluids incorporated into intraocular lenses and their methods of use. In some embodiments the fluids are silicone oils, and in some embodiments they are used in accommodating intraocular lenses.

Fluids incorporated into intraocular lenses and their methods of use. In some embodiments the fluids are silicone oils, and in some embodiments they are used in accommodating intraocular lenses.

Described is a process for producing SiOC-bonded polyether siloxanes branched in the siloxane portion from cyclic branched siloxanes of the D/T type, wherein said process comprises in a first step reacting the mixtures of cyclic branched siloxanes of the D/T type with acetic anhydride optionally in admixture with simple siloxane cycles under acid catalysis to afford acetoxy-bearing branched siloxanes, in a second step performing the equilibration of the acetoxy-modified branched siloxane with trifluoromethanesulfonic acid, preferably with addition of acetic acid, and in a third step reacting the trifluoromethanesulfonic acid-treated acetoxysiloxane with polyetherols optionally in the presence of bases and optionally in the presence of an inert solvent.

Described is a process for producing SiOC-bonded polyether siloxanes branched in the siloxane portion from cyclic branched siloxanes of the D/T type, wherein said process comprises in a first step reacting the mixtures of cyclic branched siloxanes of the D/T type with acetic anhydride optionally in admixture with simple siloxane cycles under acid catalysis to afford acetoxy-bearing branched siloxanes, in a second step performing the equilibration of the acetoxy-modified branched siloxane with trifluoromethanesulfonic acid, preferably with addition of acetic acid, and in a third step reacting the trifluoromethanesulfonic acid-treated acetoxysiloxane with polyetherols optionally in the presence of bases and optionally in the presence of an inert solvent.

A method of stabilizing imino-functional silane involving adding thereto at least one Brønsted-Lowry base to inhibit, suppress or prevent the addition reactions of the imino-functional silane with itself to form a imino- and amino-functional silane and the subsequent deamination reactions to form conjugated carbon-carbon double bond-containing imino-functional silanes and stabilized imino-functional silanes containing the at least one Brønsted-Lowry base.

A method of stabilizing imino-functional silane involving adding thereto at least one Brønsted-Lowry base to inhibit, suppress or prevent the addition reactions of the imino-functional silane with itself to form a imino- and amino-functional silane and the subsequent deamination reactions to form conjugated carbon-carbon double bond-containing imino-functional silanes and stabilized imino-functional silanes containing the at least one Brønsted-Lowry base.

The content of boron compounds in a composition containing at least one halosilane is reduced by bringing the composition into contact with at least one phenylsilane and removing the at least one halosilane. The invention further relates to the use of phenylsilanes for removing boron compounds from halosilane-containing compositions.

The content of boron compounds in a composition containing at least one halosilane is reduced by bringing the composition into contact with at least one phenylsilane and removing the at least one halosilane. The invention further relates to the use of phenylsilanes for removing boron compounds from halosilane-containing compositions.